Magnetically weighted pressure rolls



SePf- 29, 1964 c. w. AURICH 3,150,419

MAGNETICALLY WEIGHTED PRESSURE ROLLS Filed Sept. 28, 1962 20c FIGZUnited States Patent O Fce 3,156,419 MAGNETICALLY WEIGHTED PRESSUREROLLS Christoph W. Aurich, Clemson, S.C., assigner, by mesneassignments, to Maremont Corporation, Chicago, Ill., a corporation of'Iliinois Filed Sept. 28, 1962, Ser. No. 226,936 10 Claims. (Cl. 19-272)This invention relates to rolls used in applying pressure to materialmoving thereagainst, such as drafting rolls, calendering rolls and thelike. More particularly the invention relates to constructions and meansof a magnetic nature for weighting such rolls in order to apply pressureto material passing between a pai-r of rolls.

The invention is useful in drawing mechanisms of the type used intex-tile machines such as spinning, roving, drawing frames, comber drawboxes and the like, where pressure is applied to fibrous materialpassing between pairs of rolls. The invention also may be applied inanalogous paper making or processing machines where pressure is appliedby rolls to sheets or webs of stock passing between the rolls, such ascouch rolls, press rolls, calenders and the like.

In each of these mechanisms one or both of a pair of cooperating rollsis rotatably driven to carry material between the rolls, and pressure isapplied between the rolls sufiicient to cause the necessary drafting,calendering or other pressure treatment of the material for which themechanism is designed. Although weights, springs, levers and hydraulicor pneumatic pressure systems often are used to weight the upper roll orlift the lower roll in a pair in order to apply the desired pressurebetween the rolls, the present invention does not relate to suchweighting arrangements with their attendant difficulties and problemsbut relates to improvements in the magnetic weighting of rolls. Inmagnetic weighting, one or both rolls of as many pairs as may be desiredconsists of or includes a magnet, the rolls being so associated that themagnetic force pulling them together applies sufficient pressure betweenthem. No weights, springs, levers or like mechanisms for weighting `therolls are therefore required.

In prior magnetic pressure rolls the internal magnets, having lowstructural strength themselves, are contained within and supported byouter cylinders of heavy brass, bronze, aluminum or other metals ofnon-magnetic or diamagnetic character. Non-magnetic materials are usedin order to provide necessary reluctance and prevent flux loss byleakage between pole pieces at the ends of the magnets. Unfortunately,brass and such economically acceptable diamagnetic materials are notnoted for struc- Itural strength, and the sizes of prior magnetic rollsusing such materials are therefore limited. The thickness orcross-section of a brass or other non-magnetic shell, necessary toprovide mechanical strength and support, often reduces the magneticweighting effect which otherwise might be obtained because a thickershell reduces the diametrical space available for magnet accommodationfor any given outside diameter of roll. On such rolls also, the shells,the magnets and the pole pieces must be provided with structures holdingthe parts together, on or by which the gudgeons or journals forrotatably supporting the rolls can be dependably secured, and sometimesresilient cots or coverings must be mounted on such rolls.

One object of the present invention is to provide magnetic rolls for thepurposes described which are simple in construction, easy tomanufacture, compact, solid, and which may be made in smaller diameters,of greater length and of lighter weight than magnetically weighted rollspreviously available. Another object is to provide such rolls in which,by magnetic forces, higher pressures and 3 l 5 ,4 l 9 Patented Sept. 29,l 964 larger spacings between rolls may be obtained for the treatment ofheavier slivers or webs of material than heretofore. A further object isto provide improved srtuctures in such rolls for securing supportingjournals thereto and for mounting cots thereon.

The principal objects of the invention are met generally by eliminatingthe usual non-magnetic or diamagnetic tubes or sleeves surrounding themagnets and pole pieces in the rolls, and providing a strong,thin-walled tube, sleeve or cylindrical shell of steel or similarmagnetic, i.e. ferrous, magnetizable, material. Although the use of asleeve of such magnetic material would seem unduly to reduce thereluctance of the magnetic circuit, adding undesirable leakage, it hasbeen found that by using a highly permeable material and by keeping theshell wali as thin (small in cross-section) as practically possible, bymagnetically saturating the sleeve, considerable reluctance is provided,minimizing the leakage flux or flux loss. Good results are obtainedusing dimensions and proportions acceptable in equipment of the typehere involved with the shell cross-sectional area reduced to a minimumcompatible with required mechanical strength characteristics. Simplifiedconstruction of the roll is possible, as hereafter described, by virtueof the character of the shell material.

Other objects, advantages and further details of that which is believedto be novel and included in this invention will be clear from thefollowing description and claims, taken with the accompanying drawingsin which are illustrated examples of pressure rolls embodying thepresent invention and incorporating magnets enclosed within strong butthin walled shells of magnetic material such as steel.

In the drawings:

FIG. 1 is a front elevational view of a set of drawing rolls embodyingone form of this invention;

FIG. 2 is a vertical sectional view of a set of drawing rolls accordingto another form of this invention;

FIG. 3 is a front elevational view, partly in section, of a set ofcalendering rolls embodying the invention;

FIG. 4 is an enlarged vertical sectional view through the end of one ofthe top rolls in the form of FIG. l;

FIG. 5 is a similar enlarged sectional View of the end ofthe top roll inthe form of FIG. 2, and

FIG. 6 is a corresponding enlarged sectional view through the end ofIthe bottom roll in the form of FIG. 2.

In the various figures of the drawings the same basic elements in thedifferent forms of the invention are given the same numbers throughout,with the addition of differentiating letters to identify Variations inform of these elements.

Drafting mechanisms of the type shown in FIG. 1 include a series of toprolls 10, shown in detail in FIG. 4, and a single bottom roll or shaft12 suitably rotated by a drive (not shown) in a manner well known.Protuberant annular bosses of resilient material, 14, also sometimescalled cots or covers, are provided on the top rolls and receive powerfrom the rotating bottom rolls by contact with areas of fine fluting orribs 16 on the bottom roll. The cooperating cots and fluted sectionsproduce a continuously uniform bite or nip and conform to the sllape ofa sliver or other fibrous material fed between t ern.

The upper rolls in this form are provided with gudgeons 20 at their endsjournaled in slots in cap bars 22 as is usual in this type of draftingmechanism. The driven lower roll or shaft is suitably supported andjournaled as in a roll stand at 18.

In order properly to weight the rolls and apply the desired pressurebetween the resilient bosses and cooperating tinted sections, each ofthe top rolls in the form of FIGS..

l and 4 is provided with and consists principally of a permanent magnet2S of cylindrical form, which, according to this invention, is closelysurrounded by a, uniformly thin shell 30 of steel or similarstructurally strong metal capable of being magnetized. At each end ofthe magnet, held tightly thereagainst, a pole piece is provided whichpreferably is secured directly to or fabricated integrally with one ofthe gudgeons Ztl. The pole pieces, preferably of soft steel, are pressedand secured tightly within the ends of the cylindrical shell and againstthe magnet ends by spinning over or rolling the edges of the shell, bywelding, or in some other suitable` fashion as at 34. Immediatelyoutside of the pole Pieces, on either end gudgeon of each top roll ofthis form, the cots 1li above mentioned are secured as by slipped overthe gudgeons and cemented or otherwise lirmly secured to rotatesimultaneously with the rest of the top roll.

The bottom roll or shaft 12 in this form may be made entirely ofmagnetic steel so that the magnetic iiux from the pole pieces at theends of the magnet attracts each top roll toward the bottom roll shaftwith the proper weight or pressure. When the cross section of the steelshell of the top roll is made thin enough, magnetic saturation isreadily achieved and a condition of reluctance is created whereby theloss due to leakage through the shell from pole piece to pole piece isminimized. Highly oriented magnets like those sold under the name ALNICOV have been found to be eminently satisfactory in rolls according tothis invention even though such magnets are relatively low inmechanicalor structural strength. The thin tubular sleeve of magneticsteel provides the necessary structural strength without, however,producing objectionable iiux loss due to leakage, and constitutes thesole element supporting and holding together the magnet, p ole piecesand roll-supporting gudgeons. Note that the shell is of uniformcross-section through its length, having no weak spots.

This basic roll construction lends itself also to the use of more thanone magnet, and a plurality of magnets can be used aligned end to end asshown in FlGS. 2 and 3, making it possible to employ magnetic weightedrollers of small diameter but of great length. In the form of FIG. 2,for example, a single elongated top roll ltb, shown in detail in FlG. 5,is provided with a rubber or similar resilient cot or covering 14hextending its full length. Gudgeons 2Gb and end pole pieces ZltrareVprovided, closing the ends of a thin steel tube or sleeve 3% in which aplurality of magnets 28a are closely fitted. The p ole` pieces aresecured Within the shell as at 3412 in some suitable fashion such as waspreviously mentioned in connection with the embodiment shown in FIGS. land 4. Between the ends of the several magnets in this roll anintermediate pole piece 2da is mounted, such intermediate pole piecesbeing in the form of a disk closely iitting the tube and against themagnet ends, the adjacent poles of the magnets in the roll both being ofthe same polarity so that a series of magnetic elds is provided alongthe roll.

In this form, the drive shaft or bottom roll 12b, shown in detail inFIG. 6, may be made of magnetic steel as in the first form illustratedand described but with the liuting 16h extended for the entire length ofthe roll to match the full length cot 14h on the top roll. However, andindicating that magnets may be used in the bottom roll as well as in thetop roll, magnets 28h may be provided in the bottom roll as shown, thesemagnets being closely surrounded by a thin walled steel shell 32h onwhich the tintes lob are formed or provided. End pole pieces 24h aresecured to the drive shaft ends 12b, as at 34C in a suitable fashionsuch as was previously described in connection with the otherembodiments, and an intermediate pole piece 26h in the bottom roll ispositioned opposite corresponding pole piece 26a in the top roll when aplurality of magnets is used in both the bottom and top roll. As shown,the polarity position of the magnets in the bottom roll is reversed fromthat of the magnets in the top roll in this double magnetic rollassembly and greatly increased pressures or weights may be obtained withthis arrangement.

As may be seen from FlG. 3 it is further possible to use the basic steelsleeve construction as described above for calender or compression rollswhere a hard, smooth outer roll surface is desired. Accordingly, theform of invention illustrated in FIG. 3 includes a bottom roll or shaft12C containing magnets 23e, end pole pieces 24e and an intermediate polepiece 26C, all manufactured and assembled like the bottom roll of FIG.2, but without any fluting on the outside of the steel shell 32e.Cooperating with this magnetic bottom roll is a smooth hard surfaced toproll lil@ which may be made of solid Steel with gudgcons Ztlc.Alternatively this top roll might be a shell, provided with internalmagnets and pole pieces in much the same fashion as the top roll of FiG.2, but Without a resilient covering or cot.

It will be apparent that the invention may be applied to roll sets whereeither the top or bottom roll or both rolls contain magnets. It alsoshould be understood that resilient cots may be employed and the steelsleeve or tubing containing the magnets can carry iiutings of knowncross section to increase the grip, but plain surfaces also may beprovided. Although there is a certain leakage iux through the steeltubing from pole piece to pole piece, if the wall of the tubing is thinenough and is magnetically saturated, the permeability of the sleeve islowered and makes available a high percentage of useful flux forattracting either nonmagnetized ferrous or magnetized companion rolls.

Another interesting phenomenon is exhibited by magnetic rolls accordingto this invention. That is, the magnetically saturated steel shellaround the magnet makes the roll less sensitive to demagnetization. Inother words adjacent magnetic fields will have less effect on rolls ofthe present invention than on rolls of more conventional design.

As will be evident from the foregoing description, certain aspects ofthis invention are not limited to the particular details set forth asexamples, and it is contemplated that various and other modificationsand applications of the invention will occur to those skilled in theart. It is therefore intended that the appended claims shall cover suchmodifications and applications as do not depart from the true spirit andscope of the invention.

What is claimed as new and is desired to be secured by Letters Patent ofthe United States is:

1. In a magnetic pressure roll set comprising a first roll withcylindrical permanent magnet means therein,

magnetic pole pieces at the ends of the magnet,

a hollow cylindrical outer shell of uniform cross-section closelysurrounding and enclosing said magnet and pole pieces,

means rotatably mounting said first roll, and

a second roll of magnetic character rotatably mounted next to said firstroll for pressure-creating cooperation therewith by influence ofmagnetic liuX from the said magnet and pole pieces of said first roll,

that improvement in which said shell in said first roll is of magneticmaterial of such thin cross-section that said permanent magnet meansmaintains said shell in magnetically saturated condition, suflicientreluctance thereby being pro,- vided minimizing magnetic flux loss frompole piece to pole piece and said shell containing said magnet and polepieces and constituting structural support of the same in said roll andof said roll in its mounting.

2. That improvement in a magnetic pressure roll set as claimed in claiml in which the magnetic material of said shell is steel.

3. That improvement in a magnetic pressure roll set as claimed in claim1 wherein the means rotatably mounting said first roll comprises a pairof gudgeons integral with said pole pieces at the ends of said roll.

4. A roll set as claimed in claim 1 in which said rolls are draftingrolls and one said roll carries an annular resilient cot thereon,`

while said other roll is provided with a iinely fluted section oppositesaid cot to cooperate therewith in drafting material passing betweensaid rolls.

5. A roll set as claimed in claim 1 in which said rolls are calenderingrolls and both rolls are provided with cooperating hard, smooth outersurfaces to calender material passing between said rolls.

6. A magnetic pressure roll for the purposes described comprising anouter hollow cylindrical shell of uniform thin crosssection,

permanent magnet means including at least one cylindrical magnet closelyfitted within said outer shell,

a pair of soft steel pole piece disks of the same diameter as saidcylindrical magnet fitted within and closing the ends of said shell,bearing tightly against the ends of said magnet and means securing saidpole piece disks within the ends of said shell and holding said magnettightly in the shell between the disks,

said shell constituting structural support of said magnet and pole piecedisks in the shell and being of ferromagnetic material of such saiduniform thin crosssection that said permanent magnet means maintainssaid shell in magnetically saturated condition, suicient reluctancethereby being provided minimizing magnetic flux loss from pole piecedisk to pole piece disk in the shell. f

7. A pressure roll as claimed in claim 6 in which said magnetic meanscomprises a plurality of cylindrical magnets closely fitted end to endwithin said outer shell with a soft steel pole piece disk between theends of adjacent magnets.

8. A pressure roll as claimed in claim 6 including a pair of outwardlyextending gudgeons, one on each of said pole piece disks, for rotatablysupporting said roll at its ends.

9. A pressure roll as claimed in claim 8 in which each of said gudgeonsis formed integrally with a said pole piece disk.

10. In a magnetic pressure roll set comprising a iirst roll withcylindrical permanent magnet means therein,

magnetic pole pieces at the ends of the magnet,

a hollow cylindrical outer shell of uniform cross-section closelysurrounding and enclosing said magnet and pole pieces,

means rotatably mounting said rst roll, and

a second roll of magnetic character rotatably mounted next to said firstroll for pressure-creating cooperation therewith by influence ofmagnetic flux from the said magnet and pole pieces of said rst roll,

that improvement in which said shell in said first roll is of ferrousmaterial of such thin cross-section that said permanent magnet meansmaintains said shell in magnetically saturated condition, sucientreluctance thereby being provided minimizing magnetic flux loss frompole piece to pole piece and said shell containing said magnet and polepieces and constituting the sole structural support of the same in saidroll and of said roll in its mounting.

References Cited in the le of this patent UNITED STATES PATENTS2,686,940 Burnham Aug. 24, 1954 2,951,266 Burnham Sept. 6, 19603,079,646 Burnham Mar. 5, 1963 FOREIGN PATENTS 878,256 Great BritainSept. 27, 1961

10. IN A MAGNETIC PRESSURE ROLL SET COMPRISING A FIRST ROLL WITHCYLINDRICAL PERMANENT MAGNET MEANS THEREIN, MAGNETIC POLE PIECES AT THEENDS OF THE MAGNET, A HOLLOW CYLINDRICAL OUTER SHELL OF UNIFORMCROSS-SECTION CLOSELY SURROUNDING AND ENCLOSING SAID MAGNET AND POLEPIECES, MEANS ROTATABLY MOUNTING SAID FIRST ROLL, AND A SECOND ROLL OFMAGNETIC CHARACTER ROTATABLY MOUNTED NEXT TO SAID FIRST ROLL FORPRESSURE-CREATING COOPERATION THEREWITH BY INFLUENCE OF MAGNETIC FLUXFROM THE SAID MAGNET AND POLE PIECES OF SAID FIRST ROLL, THATIMPROVEMENT IN WHICH SAID SHELL IN SAID FIRST ROLL IS OF FERROUSMATERIAL OF SUCH THIN CROSS-SECTION THAT SAID PERMANENT MAGNET MEANSMAINTAINS SAID SHELL IN MAGNETICALLY SATURATED CONDITION, SUFFICIENTRELUCTANCE THEREBY BEING PROVIDED MINIMIZING MAGNETIC FLUX LOSS POLEPIECE TO POLE PIECE AND SAID SHELL CONTAINING SAID MAGNET AND POLEPIECES AND CONSTITUTING THE SOLE STRUCTURAL SUPPORT OF THE SAME IN SAIDROLL AND OF SAID ROLL IN ITS MOUNTING.